A Hybrid Model for QCD Deconfining Phase Boundary

TL;DR

This paper introduces a hybrid model combining a new hadron gas EOS and a quasiparticle QGP model to map the QCD phase boundary, predict the critical point, and analyze phase transition characteristics at finite baryon chemical potential.

Contribution

The paper develops a hybrid model that effectively describes QCD matter at finite temperature and chemical potential, enabling predictions of phase transition details and the critical point location.

Findings

Successfully reproduces lattice QCD data at zero chemical potential.

Predicts the QCD phase boundary and critical point at finite chemical potential.

Demonstrates the model's utility in analyzing phase transition order and nature.

Abstract

Intensive search for a proper and realistic equations of state (EOS) is still continued for studying the phase diagram existing between quark gluon plasma (QGP) and hadron gas (HG) phases. Lattice calculations provide such EOS for the strongly interacting matter at finite temperature ($T$) and vanishing baryon chemical potential ($\mu_{B}$). These calculations are of limited use at finite $\mu_{B}$ due to the appearance of notorious sign problem. In the recent past, we had constructed a hybrid model description for the QGP as well as HG phases where we make use of a new excluded-volume model for HG and a thermodynamically-consistent quasiparticle model for the QGP phase and used them further to get QCD phase boundary and a critical point. Since then many lattice calculations have appeared showing various thermal and transport properties of QCD matter at finite $T$ and $\mu_{B}=0$. We test our hybrid model by reproducing the entire data for strongly interacting matter and predict our results at finite $\mu_{B}$ so that they can be tested in future. Finally we demonstrate the utility of the model in fixing the precise location, the order of the phase transition and the nature of CP existing on the QCD phase diagram. We thus emphasize the suitability of the hybrid model as formulated here in providing a realistic EOS for the strongly interacting matter.